C8051F34A-GMR Silicon Labs, C8051F34A-GMR Datasheet - Page 43

• Manufacturer Part Number: C8051F34A-GMR
• Description: 8-bit Microcontrollers - MCU 48 MIPS 64KB 10ADC
• Manufacturer: Silicon Labs

Specifications of C8051F34A-GMR

• Rohs: yes
• Core: 8051
• Processor Series: C8051
• Data Bus Width: 8 bit

5.2.
The temperature sensor transfer function is shown in Figure 5.2. The output voltage (V
ADC input when the temperature sensor is selected by bits AMX0P4-0 in register AMX0P. Values for the
Offset and Slope parameters can be found in Table 5.1.
The uncalibrated temperature sensor output is extremely linear and suitable for relative temperature mea-
surements (see Table 5.1 for linearity specifications). For absolute temperature measurements, offset and/
or gain calibration is recommended. Typically a 1-point (offset) calibration includes the following steps:
Figure 5.3 shows the typical temperature sensor error assuming a 1-point calibration at 25 °C. Note that
parameters which affect ADC measurement, in particular the voltage reference value, will also
affect temperature measurement.
Temperature Sensor
Step 1. Control/measure the ambient temperature (this temperature must be known).
Step 2. Power the device, and delay for a few seconds to allow for self-heating.
Step 3. Perform an ADC conversion with the temperature sensor selected as the positive input
Step 4. Calculate the offset characteristics, and store this value in non-volatile memory for use
and GND selected as the negative input.
with subsequent temperature sensor measurements.
Figure 5.2.
C8051F340/1/2/3/4/5/6/7/8/9/A/B/C/D
V
Temp
TEMP
C
=
= (V
Temperature Sensor Transfer Function
(Gain
TEMP
x Temp
- Offset) /
Temperature
Rev. 1.3
C
) +
Offset
Offset
Gain
(V at 0 Celsius)
Gain
(V / deg C)
TEMP
) is the positive
43